Power regulator systems can be implemented in a variety of electronic devices for regulating an output voltage to provide power to one or more circuit components in the electronic device. One such type of power regulator system is a switching power regulator, such as a buck converter, in which high-side and low-side switches are alternately activated to generate a switching voltage that provides an output current through an output inductor to generate an output voltage. Some power regulator systems implement a transformer-coupled gate-drive in the input stage to provide substantially greater power efficiency, such as based on controlling a power switch based on a voltage generated at a secondary winding of the transformer in the input stage.